Understanding biomolecules and their interaction with solvent such
as water is essential to revealing mechanisms and functions of
biological systems. While atomistic simulations that treat both
solvent and solute molecules explicitly are accurate, the recently
developed implicit solvent models for biomolecules greatly reduce
the degree of freedom in simulations.

In this talk, I will first introduce a class of variational implicit
solvent models for biomolecules. I will then present my recent work,
jointly with L.-T. Cheng, J. Dzubiella, and J. A. McCammon, on level-set
calculations of equilibrium solvent-solute interface and free-energy
for nonpolar solvation systems. Finally, I will introduce generalized
Born models for the electrostatics calculations in implicit solvent
models; and examine the validity of various formulas of generalized
Born radii.